Air cleaner



Nov. 21, 1939.

E. w. GRAHAM AIR CLEANER Filed July 14, 1956 2 Sheets-Sheet l yQvAVw/m ATTORNEYS Nov. 21, 1939.

E. w. GRAHAM AIR CLEANER Filed July 14, 1936 2 Sheets-Sheet 2 INVENTOR 2370252 W Graham ATTORNEY Patented Nov. 21-, 1939 PATENT OFFICE .AYIR CLEANER.

Erwin William Graham, Madison, Wis., assignor to Burgess Battery Company, Madison, Wis., a corporation oi Wisconsin Application July 14-, 1936, Serial No. 90,452

3 Claims.- (31- 18315) This invention relates to air cleaners for internal combustion engines, air compressors and the like, and particularly to the type of air cleaner which contains a bath'of liquid, usually .oil, arranged to be mixed with the incoming air in such manner that the contained dust and dirt is washed out of the air.

In air cleaners of said type, it is diflicult to obtain uniformly satisfactory air cleaning action at, the difierent speeds at which the engine is operated. This is particularly true where the air cleaners are applied to automobile engines which are operated at widely varying speeds. Furthermore, at high engine speeds the air passes through the air cleaner at high velocities and tends to carrythe liquid'out of the cleaner. To prevent this action most of the present air cleaners have baflles arranged across the path of the air.

It is the object of the invention to providean air cleaner of the liquid bath type which is simple and economical of construction and which provides highly efllcient air cleaning action.

It is a further object of the invention to provide a liquid bath air cleaner which provides highly eflicient air cleaning action over a wide range of engine speeds and which retains the air cleaning liquid therein under conditions or high" air velocities. p

It is afurther object of the invention to provide an interstitial air filtering mass for liquid bath air cleaners which is particularly 'efiective for preventing the liquid from being carried out of the air cleaner by air passing therethrough at high velocity.

In the drawings: I

Fig. 1 is a side view, partly in "section, of the air cleaner;

Fig. 2 is a bottom view;

Fig. 3 is a diagrammatic view of a mechanism for forming the interstitial filtering means; and

Fig. 4 is a top sectional view of the interstitial filtering unit of my air cleaner at an intermediate stage in production.

- The air cleaner comprises an exterior casing- III which is generally cylindrical in shape and has a series of air entrance openings l2 extending around the upper portion of the sidewall.

The casing is further provided-with a. substantially central opening in the bottom wall through which an air'discharge conduit l4 extends. The portions of the casing above and belowopenings I2 are connected by diagonal webs IS. The bottom wall of the casing It has an annular depression it formed around the outer border there;:

" described more in detail hereinafter.

fined between solid frame side walls 26iand 28, .20

'middle portion of the bottom end of the interbody 24. I

rests upon the wall It and an edge portion 38 projects outwardly into thesump l6. Spaced lugs 38Jare formed integrally with the inner of to form a sump for the 'oil. Along the inner" edge of the sump It, the casing bottom is de- I formed upwardly to form the sump wall [-8. Inwardly of the sump wall l8, the casing bottom .is deformed downwardly to form a second sump 5 a 20. Since the normal oil level is above wall id it may be regarded that there is but a single sump in the casing. The total sump capacity is such that when the casing is filled to the proper level it contains the desired amount of oil.

Above the'air entrance openings l2, the side wall of the casing In is turned inwardly-a short distance to a point 2| where it is turned upwardly again and is formed into a dome-shaped top 22. Within the casing and surrounding the .1

air discharge tube M, an annular filter body 24 is arranged. The filter body comprises an interstitial mass of strand material which'will be It is -on'- whichextend over and cover the marginal portions of the bottom end of interstitial body 24. The bottom end portion 21 of frame wall 26 is curved in substantially semi-circular form. The

stitialbody 24 is confined by an open mesh screen 32. The top end of the body 24 is confined by a cover 30 which may be joined to side wall 28 by welding and to side wall 26 by the crimping of top 22 as shown at the point 2|. The marginal portions of cover 30. are solid while the middle portion is largely open to permit the ready flow of air. A substantially horizontal bafile 34 is arranged between the bottom wall of, casing l0 and the bottom end of the interstitial The outermarginal portion of baflle marginal portions of baflle 34 and are turned upwardly. These lugs are adapted to press against the bottom of interstitial body 24. Baflle 34 is held firmly in place by pressure and need not be attached to other parts of, the air cleaner. The bottom end of discharge conduit I4 is provided with an adapter l5 for connecting the air cleaner to the intake of an-internal combustion engine carburetor. The casing III is filled with oil to the level indicated by the numeral 40.

In operation, air enters at openings 12 and is directed downwardly toward the sump l6 by the wall 26. The air encounters the oil in the sump and then turns inwardly and upwardly and passes upwardly through the interstitial body 24. The

again and passes downwardly through the discharge conduit 14 into the carburetor intake. A considerable'proportion of the dust and dirt particles which are contained in the air do not follow the first reversal of direction and drop into the outer oil sump [6 where they settle xupon the bottom and are retained. The, wall [8 confines these particles to the outer sump and they settle to the bottom quickly and remain there. The curved surface 21 and the broad top of sump wall l8 provide a smooth flow of air and prevent eddy-currents from being set up in the bottom portion of the casing Ill. The area between surface 21 and wall I8 is constricted and the air flow is relatively rapid. The oil is picked up from the sump by the air and is mixed with the air and carried upwardly into the interstitial body 24. The oil level 40 is arranged in sufiiciently close proximity to the surface 21 to cause the entrapment of considerable quantities of oil.

The moving air causes the body of oil .to pile up in the inner portion of the casing in the form of asloping column. This column does not reach an equilibrium but undergoes an alternating rising and falling action. First it builds upto a maximum and then falls back to a minimum after which it again builds up to a maximum. A sort of oscillating action takes place. During the time that the column is falling, the oil flows back into the constricted area and when the column has fallen low there is more oil in this space than there would be at any time if a steady equilibrium were reached and maintained. The entrapped oil washes the air both in the space below the interstitial body 24 and in the lower portion of the body itself. As a result of the oscillating action described, more oil mixes with the air and the washing of the air is more thorough than it would be if a steady equilibrium of the oil column were maintained. This action takes place at low speeds as well as high, and the beneficial effect at low speeds is most valuable because it usually is difiicult to secure thorough cleaning at low speeds. The air cleaner of this invention is uniformly effective over a wide range of engine speeds.

The oil is separated from the air in the interstitial body and travels back downwardly into the sump carrying the dirt and dust with it. The solid coverings for the marginal portions on the bottom and top ends of the interstitial body 24, cause the main body 'of the air to flow through the middle portion of the interstitial body. This promotes the thoroughness of the air washing operation and in addition provides a relatively quiet zone along the borders of the body within which the oil returns relatively freely to the sump. There is a continuous movement of oil outwardly from the middle portion of the body toward the borders and then downwardly to the sump. This movement assists in preventing the oil from being carried out of the interstitial body and into the discharge conduit and the'engine. The main portion of bafile 34 is located a short distance below the oil level. This bafiie has a retarding effect upon the action of the air stream upon the oil. The projecting portion 36 has a definite retarding effect upon the movement of the oil and the main portion of the bafiie holds the oil in inner sump 20. Baille 34 is needed only when the engine is operated at extremely high speeds when the air, rushing through the air cleaner at high. velocities, would otherwise carry a portion of the oil through the filtering unit 24 and into the discharge conduit and the' engine. For all speeds discharge conduit I4 is accomplished smoothly and with a minimum amount of eddy-currents and resistance to flow.

The air entranceopenings 12 are arranged in such a manner as to provide substantially unlform air fiow throughout the periphery of the casing. The webs of metal I3 between the openlar shape and each alternate opening is oppositely oriented. The result is that the vertical length of total opening is substantially the same at any point, and the total opening area is substantially the same for any equal length about the perimeter of the casing. The webs l3 extend in diagonal directions and substantially the same result may be obtained by different diagonal arrangements from that shown in Fig. 1. For instance, they may all extend in the same diagonal direction. However, such an arrangement provides somewhat less structural strength in the connection between the upper and lower portions of the casing than that provided by the arrangement shown. If the webs extend vertically the effect of the obstruction to air how by the webs is present at the points where the air stream encounters the bath of oil and also whereit encounters the filtering unit. At the areas directly rearwardly of the webs there is turbulence and reduced air fiow. These portions of the oil bath and the interstitial body are not utilized as fully as the other portions.

The air cleaner is so constructed that it is separable into several parts for convenience in manufacturing, installing and cleaning after it has been in use. The top 22 and the interstitial body 24 are permanently joined together at the point 2|. The side and bottom walls of easing II! are integral and discharge conduit I4 is permanently joined to the bottom wall. The baflle 34 and the adapter I 5 are separate parts. For uniting the parts and installing the air cleaner the top 22 is provided with apart 42 spaced upwardly from the central portion of top 22. The central portion of top 22 and part 42 are provided with aligned openings through which a bolt 44 may be inserted. The adapter l5 fits over the end of the intake pipe (not shown) with which the engine carburetor is commonly provided. A collar 46'is provided about the lower end of the adapter l5 and is adapted to be tightened upon the carburetor intake by means of the threaded bolt 48. The adapter is provided with a flexible gasket 50 for the purpose of preventing leaks between the air cleaner and the carburetor intake. A bracket 5| extends diametrically across the adapter and has a tapped opening 52 at the center to receive the threaded end of bolt 44. The upper part of the inner wall 28 of the air filter unit 24 is provided with an inwardly extending flange 53 which is provided with a gasket 54.

For assembling the air cleaner, baffle 34 may be placed in'the open casing shell l0 and the top ings are narrow and the openings are of trianguthreaded into opening 52 in bracket 5| and all of the parts are drawn tightly together in this manner. Baflle 34 is held in place under pressure between filter unit 24 and the bottom wall of the casing Ill. The adapter may then be fitted over the end of the engine carburetor intake and tightenedin place by tightening bolt 48 ,on collar 46 It may be inconvenient to manipulate bolt 48 while the air cleaner is in place because of limitations of space. In such case the adapter l5 may be tightened upon the carburetor first, and then the air cleaner assembly may be fitted upon the adapter and finally bolt 44 may be threaded into place to draw the air cleaner assembly tightly into place upon the adapter. w When it .is desired to wash the accumulated dust and dirt from the air cleaner, bolt 44 is unscrewed and the air cleaner removed. The'filtering unit andthe casing shell may be taken apart and washed separately. Clean oil may then be placed in the casing shell and the parts reassembled and tightened upon the adapter by means of the bolt 44. The fact that the air cleaner is constructed of separable parts as described results in simplicity and economy of manufacture.

The interstitial body 24 is designed to provide maximum air cleaning efficiency and maximum retarding effect upon the tendency of the air to carry the oil out of the air cleaner and into the engine. The filtering material is of the metallic oil out of the air cleaner, much more so than the straight or the wavy strand materials that have been used heretofore. A unique method of ar-' ranging the strand material is usedin order to sidewise to form zigzags.

secure the optimum porosity characteristics and uniformity of distribution throughout the volume of the interstitial body. The annular enclosing frame for the body, without'the cover 30, is arranged on a support which is adapted to revolve the frame about its vertical axis.- One or more of the gimped strands are fed by a suitable feeding device and allowed to fall freely into the open topped frame whilethe latter is being revolved. The rate of movement of the frame is considerably slower than the rate of feed of the strand material. As a result the strand material is not carried away upon the support as fast as it is deposited and there is an accumulation. The

accumulation causes swinging of the strand around to form loops and back and forth and Fig. 3 illustrates in diagrammatic fashion the deposition. of the strands in the air filter frame. The frame is carried upon a platform 56 which is adapted to be rotated upon a support 58. The strand material faced. with a soft material, such, as, soft rubber and the other roll provided with teeth or other spaced projections which engage the coils of the strand. The strand may then proceed through aguide 66 located a suitable distance above the frame and then drops freely into the annular frame. The swinging back and forth illustrated at and the curling into loops I0 is theresult of the natural movement of the strand as it accumulates in the relatively slowly revolving 'side and the formation of the loops are shown.

The relative speeds at which the strand-is fed and the frame is rotated determine the frequency and the size and character of the loops and the weavingfrom side to side. Considerable latitude is permissible in' this respect.

the ready formation of the loops and other irregularities. A height of about two feet above the bottom of the frame has been found to be satisfactory. The amount of material for each filtering unit is usually determined by weight and after this amount has been fed into the frame, it is compressed sufilciently so that the cover 30 may be attached.

The successive layers of the strands cross and re-cross each other in a heterogeneous but orderly manner. Such crosswise arrangement .of gimped strands results in an open interstitial .mass which is more suited for an oil bath air The strand should be fed from a height suflicient to permit cleaner than the more closed mass which results when a simple circular arrangement of gimped strands is used. In addition, the porosity characteristics and the distributionof strand material issubstantially uniform throughout .the

volume of themass. When the proper character of gimped strand is used the mass possesses elasticity and resists packing down with use. An

automobile air cleaner is subjected to vibration which tends to pack down the mass of strands.

The gimped strands are .composed of metal, preferably copper, rolled or drawn, into ribbon ,form. There is an optimum size for best results,

with respect to both the transverse dimensions of the strands-and the diameter of the helical coils. Both of these factors affect the size of the pores, which should be maintained within a more or less limited range for best results. If the pores are too large the air passes through the mass without undergoing a thorough cleaning too large the distribution is not uniform and the mass possess-es 'insufficient elasticity to resist packing down with use. If the dimensions are too small the strands do not possess sufiicient strength and the mass lacks the elasticity necessary to maintain the porosity uniform and prevent packing down.

The strand material which I have found to be suited to the purpose is composed of copperand comprises one helically coiledstrand wound about one straight carrier strand. The coils are, on the average, about three-sixteenths inch in diameter,

carrier strand or of both of them and various combinations have been used successfully. If the transverse dimensions of the strand are too small, the resilience of the strand is lessened and the elasticity of the-filtering mass reduced to the extent that it packs down with use. The diameter of the helical coils may be varied, one-eighth inch coils having been used successfully.

A body of the filtering material described possesses elasticity and expands to a normal volume when the pressureis released after it has been compressed below such normal value. It is arranged in the frame at substantially this volume or at a volume which is slightly less and it maintains such volume without packing down when it is in use. This arrangement results in porosity characteristics which combine maximum filtering efliciency and maximum retarding effect against carrying of the oil out of the air cleaner by air at high velocity. In prior oil bath air cleaners, it has been necessary to interpose mechanical baffles across the path of the air stream to prevent the escape of oil. In the air cleaner of this invention such a bafiie ordinarily is not required, the baflle 34 being used only under condition where such high speeds are encountered as may be considered abnormal.

The invention is not limited to the construction described herein. A single operative example is described and illustrated and the invention embraces such variations, both in the general structural features and the character of the strand material, as may be made by those skilled in the art.

I claim:

1. In an air cleaner, a casing having air inlet and discharge openings therein and having a liquid sump in the bottom thereof, an interstitial mass of filtering material arranged above said liquid sump, said casing having an air passage therethrough leading from said inlet opening downwardly toward and adjacent said sump and upwardly from said sump and through said filter to said outlet opening, a bafiie member spaced from the bottom wall of said sump, and a partition connecting intermediate portions of said baffle and the bottom wall of said sump, said partition extending transversely of the path of air travel, said bafiie member being constructed and arranged to provide a passageway to the liquid below said bafile on each side of the partition.

2. In an air cleaner, a casing having air inlet and outlet openings therein and having a liquid sump in the bottom thereof, an interstitial mass of filtering material arranged above said liquid sump, said casing having an 'air passage therethrough leading from said inlet opening downwardly toward and adjacent said sump and upwardly from said sump and through said filter to said outlet opening, a generally horizontal baflle below the initial level of said sump and spaced from the bottom wall of said sump, and a partition projecting upwardly from an intermediate portion of the bottom wall of said sump and engaging an intermediate portion of said bafile to separate the bodies of liquid on the opposite sides of said par- .tition, said partition extending transversely of the path of air travel, said bafile being constructed and arranged to provide a passageway to the liquid below said baflie on each side of said partition, said baflie having a bend therein to provide an enlargement of said air passage in advance of said filter.

3. In an air cleaner, a casing having a substantially cylindrical side wall, said side wall having a peripheral air inlet opening'therein, a substantially central 'discharge conduit extending through the bottom wall of said casing, an intermediate substantially cylindrical wall spaced inwardly from said side wall and arranged to form an air passage extending downwardly from said inlet opening toward the bottom of said casing and upwardly to said discharge conduit, an annular filter mass within said upward air passage between said discharge conduit and said intermediate wall, a liquid sump in the bottom of said casing in spaced relation to the bottom of said filter, and adjacent said air passage, a generally horizontalbaflie spaced from the bottom Wall of said sump, and a partition extending transversely 1 of the path of air travel and connecting intermediate portions of said baflle and the bottom wall of said sump to separate the bodies of liquid on opposite sides of said partition, said bafile member being constructed and arranged to provide a passageway to the liquid below said bafile on each sideof said partition.

ERWIN WILLIAM GRAHAM. 

